Leaky-wave antennas, which consist of a waveguide structure that allows low-level continuous Radio Frequency (RF) radiation along the length of the guiding structure, are used in a number of applications including communications applications such as 5G networks and satellite communication. To ensure radiation is directed in a fixed direction, typical leaky-wave antennas require that, at a given frequency, the propagation constant of a radiated field along the structure be kept constant. As a result, typical leaky-wave antennas have uniform aperture geometries. This configuration results in a natural exponential decay in amplitude from the feed point along the aperture of the antenna. The asymmetrical amplitude tapering field typically results in poor sidelobe performance in the radiation patterns for such antennas. Further, a typical leaky-wave antenna permits angular scan in fixed frequency only, and can only scan in approximately half of the available space (e.g., <90 degrees) due to the inherent positive propagation constant of the antenna.
Metamaterials (MTM) are artificial structures that behave differently from natural right-hand materials alone. A metamaterial may be made to operate in either or both left-handed and right-handed mode. Such materials are referred to as composite right-left-handed (CRLH) metamaterials. CRLH metamaterials can be engineered using conventional dielectric and conductive materials to produce unique electromagnetic properties.
CRLH metamaterial components may be fabricated on various substrates or circuit platforms such as conventional Printed Circuit Boards (PCBs) or flexible PCBs, providing an easily manufactured, inexpensive solution. The substrate may include a ground plane or a surface having a truncated or patterned ground portion or portions. Metamaterials including CRLH metamaterials can be used to construct antennas including leaky-wave antennas that avoid many of the drawbacks of conventional antennas including poor sidelobe performance and beams that are not electronically beam steerable.